An astronaut (or cosmonaut) is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft. Although generally reserved for professional space travelers, the terms are sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and tourists.[1][2]

Starting in the 1950s up to 2002, astronauts were sponsored and trained exclusively by governments, either by the military or by civilian space agencies. With the suborbital flight of the privately funded SpaceShipOne in 2004, a new category of astronaut was created: the commercial astronaut.

As of 20 June 2011[update], under the U.S. definition 538 people qualify as having reached space, above 50 miles (80 km) altitude. Of eight X-15 pilots who exceeded 50 miles (80 km) in altitude, only one exceeded 100 kilometers (about 62 miles).[8] Space travelers have spent over 41,790 man-days (114.5 man-years) in space, including over 100 astronaut-days of spacewalks.[8][9] As of 2008, the man with the longest cumulative time in space is Sergei K. Krikalev, who has spent 803 days, 9 hours and 39 minutes, or 2.2 years, in space.[10][11]Peggy A. Whitson holds the record for the most time in space by a woman, 377 days.[12]

Terminology

English

In English-speaking nations, a professional space traveler is called an astronaut.[13] The term derives from the Greek words ástron (ἄστρον), meaning "star", and nautes (ναύτης), meaning "sailor". The first known use of the term "astronaut" in the modern sense was by Neil R. Jones in his short story "The Death's Head Meteor" in 1930. The word itself had been known earlier. For example, in Percy Greg's 1880 book Across the Zodiac, "astronaut" referred to a spacecraft. In Les Navigateurs de l'Infini (1925) of J.-H. Rosny aîné, the word astronautique (astronautic) was used. The word may have been inspired by "aeronaut", an older term for an air traveler first applied (in 1784) to balloonists. An early use in a non-fiction publication is Eric Frank Russell's poem "The Astronaut" in the November 1934 Bulletin of the British Interplanetary Society.[14]

NASA applies the term astronaut to any crew member aboard NASA spacecraft bound for Earth orbit or beyond. NASA also uses the term as a title for those selected to join its Astronaut Corps.[16] The European Space Agency similarly uses the term astronaut for members of its Astronaut Corps.[17]

Russian

By convention, an astronaut employed by the Russian Federal Space Agency (or its Soviet predecessor) is called a cosmonaut in English texts.[16] The word is an anglicisation of the Russian word kosmonavt (Russian: космонавтRussian pronunciation: [kəsmɐˈnaft]), one who works in space outside the Earth's atmosphere, a space traveler,[18] which derives from the Greek words kosmos (κόσμος), meaning "universe", and nautes (ναύτης), meaning "sailor". Other countries of the former Eastern Bloc use variations of the Russian word kosmonavt, such as the Polishkosmonauta.

The Soviet Air Force pilot Yuri Gagarin was the first cosmonaut—indeed the first person—in space. Valentina Tereshkova, a Russian factory worker, was the first woman in space, as well as arguably the second civilian to make it there (see below for a further discussion of civilians in space). On March 14, 1995, Norman Thagard became the first American to ride to space on board a Russian launch vehicle, and thus became the first "American cosmonaut".[citation needed]

Chinese

Official English-language texts issued by the government of China use astronaut while texts in Russian use космонавт (cosmonaut).[19][20] In official Chinese-language texts, "yǔ háng yuán" (宇航员, "space navigating personnel") is used for astronauts and cosmonauts, and "háng tiān yuán" (航天员, "space navigating personnel") is used for Chinese astronauts. The phrase "tài kōng rén" (太空人, "spaceman") is often used in Hong Kong and Taiwan.[citation needed]

The term taikonaut is used by some English-language news media organizations for professional space travelers from China.[21] The word has featured in the Longman and Oxford English dictionaries, the latter of which describes it as "a hybrid of the Chinese term taikong (space) and the Greek naut (sailor)"; the term became more common in 2003 when China sent its first astronaut Yang Liwei into space aboard the Shenzhou 5 spacecraft.[22] This is the term used by Xinhua News Agency in the English version of the Chinese People's Daily since the advent of the Chinese space program.[23] The origin of the term is unclear; as early as May 1998, Chiew Lee Yih (趙裡昱) from Malaysia, used it in newsgroups.[24][25]

While no nation other than the Russian Federation (and previously the former Soviet Union), the United States, and China have launched a manned spacecraft, several other nations have sent people into space in cooperation with one of these countries. Inspired partly by these missions, other synonyms for astronaut have entered occasional English usage. For example, the term spationaut (French spelling: spationaute) is sometimes used to describe French space travelers, from the Latin word spatium for "space", the Malay term angkasawan was used to describe participants in the Angkasawan program, and the Indian Space Research Organization hope to launch a spacecraft in 2018 that would carry vyomanauts, coined from the Sanskrit word for space.[citation needed]

The first human in space was Soviet Yuri Gagarin, who was launched on April 12, 1961 aboard Vostok 1 and orbited around the Earth for 108 minutes. The first woman in space was Soviet Valentina Tereshkova, who launched on June 16, 1963 aboard Vostok 6 and orbited Earth for almost three days.

Cosmonaut Alexei Leonov was the first person to conduct an extravehicular activity (EVA), (commonly called a "spacewalk"), on March 18, 1965, on the Soviet Union's Voskhod 2 mission. This was followed two and a half months later by astronaut Ed White who made the first American EVA on NASA's Gemini 4 mission.[27]

The first manned mission to orbit the Moon, Apollo 8, included American William Anders who was born in Hong Kong, making him the first Asian-born astronaut in 1968.

With the larger number of seats available on the Space Shuttle, the U.S. began taking international astronauts. In 1983, Ulf Merbold of West Germany became the first non-US citizen to fly in a US spacecraft. In 1984, Marc Garneau became the first of 8 Canadian astronauts to fly in space (through 2010).[36] In 1985, Rodolfo Neri Vela became the first Mexican-born person in space.[37] In 1991, Helen Sharman became the first Briton to fly in space.[38] In 2002, Mark Shuttleworth became the first citizen of an African country to fly in space, as a paying spaceflight participant.[39] In 2003, Ilan Ramon became the first Israeli to fly in space, although he died during a re-entry accident.

Civilian and non-government milestones

Depending on the exact definition of 'civilian', the first civilian in space was either Valentina Tereshkova[43] aboard Vostok 6 (she also became the first woman in space on that mission) or Joseph Albert Walker[44][45] on X-15 Flight 90 a month later. Tereshkova was only honorarily inducted into the USSR's Air Force, which had no female pilots whatsoever at that time. Joe Walker had joined the US Army Air Force but was not a member during his flight. The first people in space who had never been a member of any country's armed forces were both Konstantin Feoktistov and Boris Yegorov aboard Voskhod 1.

Training

The first NASA astronauts were selected for training in 1959.[52] Early in the space program, military jet test piloting and engineering training were often cited as prerequisites for selection as an astronaut at NASA, although neither John Glenn nor Scott Carpenter (of the Mercury Seven) had any university degree, in engineering or any other discipline at the time of their selection. Selection was initially limited to military pilots.[53][54] The earliest astronauts for both America and the USSR tended to be jet fighter pilots, and were often test pilots.

Commander and Pilot

At least 1,000 hours' flying time as pilot-in-command in jet aircraft. Experience as a test pilot is desirable.

Height must be 5 ft 2 in to 6 ft 2 in (1.58 to 1.88 m).

Distant visual acuity must be correctable to 20/20 in each eye.

The refractive surgical procedures of the eye, PRK (Photorefractive keratectomy) and LASIK, are now allowed, providing at least 1 year has passed since the date of the procedure with no permanent adverse after effects. For those applicants under final consideration, an operative report on the surgical procedure will be requested.

Mission Specialist

A bachelor's degree in engineering, biological science, physical science or mathematics, as well as at least three years of related professional experience (graduate work or studies) and an advanced degree, such as a master's degree (one to three years) or a doctoral degree (three years or more).

Applicant's height must be between 4 ft. 10.5 in. and 6 ft. 4 in.

Mission Specialist Educator

Applicants must have a bachelor's degree with teaching experience, including work at the kindergarten through twelfth grade level. An advanced degree, such as a master's degree or a doctoral degree, is not required, but is strongly desired.[56]

Health risks of space travel

Astronauts are susceptible to a variety of health risks including decompression sickness, barotrauma, immunodeficiencies, loss of bone and muscle, loss of eyesight, orthostatic intolerance, sleep disturbances, and radiation injury.[62][63][64][65][66][67][68][69][70] A variety of large scale medical studies are being conducted in space via the National Space and Biomedical Research Institute (NSBRI) to address these issues. Prominent among these is the Advanced Diagnostic Ultrasound in Microgravity Study in which astronauts (including former ISS commanders Leroy Chiao and Gennady Padalka) perform ultrasound scans under the guidance of remote experts to diagnose and potentially treat hundreds of medical conditions in space. This study's techniques are now being applied to cover professional and Olympic sports injuries as well as ultrasound performed by non-expert operators in medical and high school students. It is anticipated that remote guided ultrasound will have application on Earth in emergency and rural care situations, where access to a trained physician is often rare.[71][72][73]

Food and drink

An astronaut on the International Space Station requires about 0.83 kilograms (1.83 pounds) weight of food inclusive of food packaging per meal each day. (The packaging for each meal weighs around 0.12 kilograms - 0.27 pounds) Longer-duration missions require more food.

Shuttle astronauts worked with nutritionists to select menus that appeal to their individual tastes. Five months before flight, menus are selected and analyzed for nutritional content by the shuttle dietician. Foods are tested to see how they will react in a reduced gravity environment. Caloric requirements are determined using a basal energy expenditure (BEE) formula. On Earth, the average American uses about 35 gallons (132 liters) of water every day. On board the ISS astronauts limit water use to only about three gallons (11 liters) per day.[77]

At NASA, those who complete astronaut candidate training receive a silver lapel pin. Once they have flown in space, they receive a gold pin. U.S. astronauts who also have active-duty military status receive a special qualification badge, known as the Astronaut Badge, after participation on a spaceflight. The United States Air Force also presents an Astronaut Badge to its pilots who exceed 50 miles (80 km) in altitude.

Space Mirror Memorial

Deaths

Eighteen astronauts (fourteen men and four women) have lost their lives during four space flights. By nationality, thirteen were American (including one of Indian origin), four were Russian (Soviet Union), and one was Israeli.

Eleven people (all men) have lost their lives training for spaceflight: eight Americans and three Russians. Six of these were in crashes of training jet aircraft, one drowned during water recovery training, and four were due to fires in pure oxygen environments.

The Space Mirror Memorial, which stands on the grounds of the John F. Kennedy Space Center Visitor Complex, commemorates the lives of the men and women who have died during spaceflight and during training in the space programs of the United States. In addition to twenty NASA career astronauts, the memorial includes the names of a U.S. Air ForceX-15 test pilot, a U.S. Air Force officer who died while training for a then-classified military space program, and a civilian spaceflight participant.